Liquid Rubber Waterproof Sealant Quart - Flexible Leak Repair

In this review of the Liquid Rubber Waterproof Sealant quart, the bottom line is simple: it is best for homeowners and contractors who need a flexible, water-based barrier for roofs, gutters, foundations and other non-walking surfaces. The single biggest reason to buy is the product's combination of industrial strength bitumen chemistry and extreme elasticity, which creates a seamless rubberized membrane that stays adhered through temperature shifts and building movement.

Key Features

• Industrial bitumen formula: Forms a continuous waterproof membrane that resists water infiltration where traditional tar or patch products often fail.
• Superior flexibility: With over 950% elongation, the coating stretches with structure movement to reduce cracking and separation.
• Professional coverage specs: Can be brushed, rolled or sprayed, and provides specific coverage guidance for flat roofs and vertical surfaces to achieve the target membrane thickness.
• Water-based formula: Contains no VOCs or harsh solvents, so it is safer for enclosed or sensitive areas and cleans up with water.
• System compatibility: Works with seam tape and geo-textile to bridge joints, vents and penetrations for a more complete waterproofing solution.

Who It's For

The Liquid Rubber quart is aimed at DIYers repairing small leaks and pros doing spot repairs on flat or low slope roofs, RV roofs, chimneys, gutters, planters and foundation patches where foot traffic is minimal. Its ease of use with a paintbrush and quick drying behavior make it convenient for repair work in tight areas.

It is not suited for applications that require a walkable surface, such as patios or decks, or where a finished, decorative surface is required; the coating can remain slightly tacky after curing and is intended as a protective membrane rather than a foot-traffic finish.

Pros & Cons

Pros

• Creates a durable, seamless barrier that performs better than many conventional tar products on leaks.
• Very flexible formula resists cracking and maintains adhesion with building movement and temperature swings.
• Water-based and low-odor, making application and cleanup simpler and safer in confined spaces.
• Compatible with seam tape and geo-textile to reinforce vulnerable joints and penetrations.

Cons

• May remain tacky after curing and is not appropriate for surfaces that must be regularly walked on.
• Some users report adhesion issues in certain instances where surface preparation or existing coatings were problematic.

Specifications

Our Verdict

The Liquid Rubber quart is a practical, value-minded choice for anyone repairing leaks on roofs, gutters or foundations where a flexible, long-lasting waterproof membrane is needed. Its water-based, high-elongation formula and compatibility with reinforcement tape make it a sensible pick for both DIY projects and professional touch-ups, provided the surface is prepared and the area will not require regular foot traffic.

Frequently Asked Questions

Can I use this on a metal RV roof?
Yes. It adheres to metal and is commonly used on RV roofs, but the surface should be clean, dry and free of loose coatings for best adhesion.

Is this safe for indoor basement repairs?
Yes. The water-based formula has low odor and no VOC solvents, making it suitable for confined areas when used per instructions.

Will it crack in cold weather?
The product is formulated for superior flexibility (over 950% elongation) so it is designed to resist cracking with temperature changes and movement.